Frederick oebken



F. GE'RKEN.

, SPARK PLUG.

APPLICATION men FEB. 26. 191:

1 ,3 1 2,3 1 7 Patented Aug. 5, 1919.

IN VEN TOR.

W-ug A TTORNEYS.

nannies omen, or new man, n. Y.

seam-rum.

Specification '0: Lettcnlatent.

Patented Au 5, 191 9.

Application filed February 26, 1917. Serial ll'o. 150,908.

' T all whom. it may concern:

Be it known that I, F REDERIGK GnnKnN, a citizen of the United States oi America, and a resident of New York, in the county of New York and State of New York, have invented certain 116W and useful Im rovements in Spark-Plugs, of which the ollowin is a specification.

y invention relates to improvements in so-called spark-plugs, that is to say, 5 arking devices emplo ed for igniting the cliarges of internal com ustion engines, and also em loyed sometimes, in other connections. he improved spark plu herein described is particularl intcndec for use in engines in which, eit er because very high temperatures obtain, or for other reasons, special provision must be made for the coolin of the outcrspark terminal of the plug.

Iyinvention consists in a novel construction of the outer electrode or sparking terminal of such a plug, whereby, in connection with a particular form of inner electrode or sparking terminal, high sparking efficiency is obtained, coupled with efficient conduction of heat away from said outer sparking terminal. My invention also comprises means whereby accurate adjustment of the spark gap may be made when desired.

The object of my invention is to improve the eiiiciency of spark plugs of the type described, to insure high sparking efliciency in a plug in which provision is made for rapid conduction of heat away from the outer sparking terminal, and to provide simple and effective means for accurate adj ustment of the spark gap.

I will now roceed to describe my invention with re erence to the accom'anyin drawings, and will then point out t e nove features, in claim, in said drawings:

Figure 1 shows a side elevation of my spark plug;

F ig. 2 shows an end view of the spark I plu on a larger scale than Fig. 1;

l lg. 3 shows a fragmentar vertical section of the lower portion of t e spark plug, the section being taken on the line 3-3 of Fig. 2;

shellof the plug, provided, as usual with a threaded lower portion 2 ada ted screwed into the usual spark p u port of an englne. The lower rtion of tie shell 1 is recessed, as indicate particularly in Fig.

,3, and as is common in many spark plu s of the present day. 3 desi ates one o the spar mg terminals or eectrodes of the plug said terminal 3 being an annular member provided with a pluralit of slots 4 dlvidm its lower end into a p urality of pro ections 5, so that this terminal is of what may be called cestellated form. 6 designates the other sparking terminal or electrode of the plu having the form of a more or less thin disk, located within, and spaced, as nearly as may be, uniformly away from the projections 5 and supported upon a central 051 7.

It will 'hnderstood that this post 7 is insulated in the usual manner from the shell 1 (8,Fig. 1, designatin a portion of the insulating materia and that this post 7 is provided at its upper end with means, such as a screw nut 9, whereby one conductor of an electric circuit mav be connected to said post 7. I do not illustrate in detail the structure whereby the post 7 is insulated from the shell 1, as such structure forms no portion of the present invention, and 0rdi-.

nary means for effecting such insulation may be employed. 7

In the operation of the spark plu shown in Figs. 1, 2 and 3, owing to the act that the central electrode 6 is a smooth-edged disk, all "portions of that disk which are opposite or nearly opposite the inner surfaces of the projections 5 are available for the propagation of sparks between projections 5 and said disk 6; and in practice sparks are propagated in broad streams, almost representing or similar to flames, between these projections 5 and the disk 6, the sparks shifting from point to point along he surfaces of the projections 5, such sparks eing broad or fat, as the technical term is. and of extremely high ignition efliciency. Heat imparted to the pro ections 5 by the hot gases of the engine 0 linder is conducted back to the unslotte portion of the rin 3 and thence to the shell of the plug, an thence to the body of the en ine cylinder to which that shell is titted such body of the engine cylinder being, usually, watercooled). Owing to the relatively large cross-section of each of these projections 5,

the conduction of heat backward, in the manner described, is extremely eflicient, and thereby these rojections 5 are kept relativel cool, an so do not tend to produce re-1gnition in an engine cylinder in which, cause of high temperatures, or for other reasons, ire-ignition might otherwise be produced.

In the construction herein described, by the employment of a central terminal of disk character, the sparking points are caused to'var' widely within the limits of the inner sur ace of each individual projection 5 also, as above stated, the sparks are broad and fat. so far as my experience shows, such broad or fat sparks, and such constant varying of point of sparkin is obtainable, when using an outer electro e of castellated form, only by the employment of a central electrode of the nature of a smooth-edged disk,.and so far as I am aware, I am the first to employ, in connection with a castcllated outer electrode, -an inner electrode consisting of a sn'iooth-edgcd disk.

In some cases it is desired to be able to regulate with accuracy the spark ap between the inner and outer electro cs. In such case I rovide the outer electrode with a series 0 adjustable secondary S'JHIk points 10'as shown in Figs. 4 and 5, w are in these secondary spark points have the form of small pointed screws, each carried by one of the projections 5 and each adjustable in that projection 5, toward and from the central spark terminal, here desi nated by numeral 6. It will be obvious tiat, since each of these spark points 10 is separately adjustable, extreme meetof ad ju'stment of the spark gaps of the plug may bb obtained.

In my application for Letters Patent Serial No. 142,335. filed January 15, 1917, I

have illustrated and described a spark plug having an inner disk-terminal provided with openings to permit efi'ective cooling of that inner terminal, said disk havin however. a smooth outer edge as is t 0 case with the inner spark terminal fl and it" of the present application; and in m application filed February Ill, 1917, Serial No. 148,955, I have illustrated and described a spark plug. the inncr tcrminul of which has t ie form of a ring bent u from wire. Both of these forms of inner cicctrodes, and similar forms, are to be regarded as disk-terminals within the mcuniu of the claims of this application; since t oy are disk-terminals with more or less open centers.

Use of the secondary spark points 10 is not. of course, confined to annular terminals of the slotted or castellated structure shown in the drawings of the present application.

\Vhat I claim is:

In a spark plug, the combination with an outer spark terminal consisting of an annular member having a number of slots extending axially from one end thereof so as to give said annularmember a. castellated form, of an inner spark terminal comprising a suumth-edgcd disk having an edge of apprcciul'ile width. and a center rod supporting said disk, there being an open space ictween the interior of said outer spark terminal and said rod at least equal in width to the diameter of said rod, whereby a space for collection of explosive gas in rear of the inner terminal adequate to maintain a clear gap between said terminals, is provided, said outer spark tcrminul being provided with secondary spark points, which are screws, the ends of which face the inner spark teru'iinal, which screws may be advancrd or retracted individually toward or from said inner s ark terminal.

In testimony w ereof I have signed this specification in the presence of two subscribing witnesses.

FREDERICK GERKEN.

W i tnesscs H. M. MARBLE, PAUL H. FRANKE. 

